The Eighteenth was mustered into the service August 5, 6 and 7, 1862, with 875 officers and men, and was almost immediately ordered into Missouri, to join General Schofield’s command. During the following winter it was stationed at Springfield, and bore a conspicuous part in the battle at that place January 7 and 8, 1863. The town was defended by a battalion of Missouri militia and the Eighteenth, against an army 4,000 strong. The regiment remained here for a long time, varied by a chase of the rebel General Shelby into Arkansas, thence to Fort Smith.
In the spring of 1864, the regiment was attached to General Steele‘s command, and marched to Camden; on April 13th. was in an engagement near Moscow, thirty miles from Camden. On April 17th, received seven successive and impetuous charges from superior numbers, and returned to Camden with a loss of seventy-seven men; returned to Fort Smith, and until it was mustered out, nothing particularly noteworthy occurred.